Atomic Coherence and Optical Storage

Atomic coherence is the interaction process between light and atoms, that is one or more coherent fields couple the different atomic states and cause the quantum interference between the different transition channels. Atomic coherence has led to many interesting and unexpected consequences, such as the Hanle effects, electromagnetically induced transparency (EIT), coherence population trapping (CPT), stimulated Raman adiabatic passage (STIRAP), spontaneous emission control, resonant enhancement of optical nonlinearity, slow and superluminal light propagation, quantum light storage, etc. In which, light storage based on atomic coherence plays an important role in the coherent control of light pulse information. In this chapter, we present some previous works on atomic coherence and optical storage. Firstly, we present the storage and recovery of light pulse based on F-STIRAP, which is fundamentally different from the conventional EIT-based process. Secondly, we present the applications of light storage based on EIT in a Pr3+:Y2SiO5 crystal, which includes the erasure of stored optical information, all-optical routing by light storage, and the coherent control of double light pulses. At last, we propose theoretically and demonstrate experimentally a method to control the atomic coherence by a STIRAP or F-STIRAP process.